Monday, October 19, 2009
Angel Sit Part 3: Site Stratigraphy.
This is the third part of my continuing series on excavations at the Father Angel Site in Greene County, Pennsylvania. This part examines a concept borrowed from geology called STRATIGRAPHY. Basically, stratigraphy is layers built upon layers. Much like a wedding cake if you slice into it, you'll see a layer of cake, a layer of icing, maybe a layer of chocolate, and then another layer of cake and so on. The Earth's crust is formed in a similar way, with layer upon layer of rock built one on top of the other. So what does this have to do with archaeology? Well, archaeological sites are created in the same way. Depending on where the site is located, it may have many layers like if it were on a floodplain, or just a few layers like out in a farmer's field.
So why is stratigraphy important? To start off, let's imagine a trashcan. I throw a piece of crumpled up paper into it, and over the next few weeks, I fill it up. Then I realize that a piece of paper I threw in that first week was an important bill! Where in the trashcan would I look? Not at the top of the pile, those papers are very recent. Not in the middle either, while they're old my bill was from a week before those papers were thrown in. I would dig to the very bottom of the can because that's where the oldest pieces of paper are located. So the stratigraphy of the papers in the trashcan led me to my bill, because I knew that the oldest pieces of paper were on the bottom. This is the LAW OF SUPERPOSITION. Layers are deposited in a sequence of youngest to oldest be they sedimentary rock layers or cultural layers containing artifacts.
In this video, I'm talking about the stratigraphy of the Father Angel Site. Please turn up the volume on you speakers! For some reason, the audio is very soft!